Variable pitch aerial propeller



March 16, 1943. c. R. wAsEIGE 2,314,025

VARIABLE PITCH AERIAL PROPELLERS Original Filed July 27, 1938 4 Sheets-Sheet l Zure/2%@ March 16, 1943. c, R, WAsElGE VARIABLE FITCH AERIAL PRoPELLERs Original Filed July 2'7, 1938 4 Sheets-Sheet 2 March 16, 1943. c. R. WASEIGE VARIABLE PITCH AERIAL PROPELLERS 1958 4 'iheets--Shee-cl 5 Original Filed July 27 IIIIIIII IIIIIHII Hmm March 16, 1943. c. R. wAsElGE VARIABLE FITCH AERIAL PROPELLERS Original Filed July 27, 1938 4 Sheets-Sheet 4 Patented Mar. 16, 1943 VARIABLE m'rcn AERIAL rRoPELLEn Charles vRaymond Waseige, Rueil, France; vested v in the Alien Property Custodian original application .uuyr 27, 193s, serial No. 221,595. Divided and thisapplication November 28, 1939, Serial No. 306,564. In France July 14 Claims. (Cl. 170-163) This application is a division of earlier application filed July 27, 1938, Serial No. 221,595 (Patent 2,236,841).

The present invention relates to variable pitch aerial propellers which can be utilized on land,

'sea-going or aerial vehicles. In this kind of propeller the pitch varying mechanism often comprises a gear wheel, a sleeve or other member which is arranged coaxially with respect to the propeller shaft and drives members or groups of members distributed over the hub which are equal in number to the blades of the propeller and which are respectively associated with the various blades and cause each of same to move about its own axis, said member which is coaxial with the propeller shaft being itself connected through a transmission to a source of power formed by the actual crankshaft of the engine ory by an auxiliary electric or other motor.

One object of the invention is to provide a pitch varying and reversing device of small bulk, reduced weight, and reliable in operation, for aerial screw propellers including means adapted to increase and decrease the pitch at any one of two widely different rates. 4

Another object of the invention is to provide for the pitch variation of two tandem propellers driven by one and the same engine and rotatable relatively to one another.

By way of nonlimitative examples, a plurality of embodiments of the invention have been shown diagrammatically in the accompanying drawings, said embodiments having the above mentioned features and furthermore offering certain other peculiarities which also form detail objects -of the invention.

In said drawings:

Fig. 1 is a longitudinal vertical section through the axis of the propeller shaft of an embodiment of the invention in the case of a single propeller;

Fig. 2 is a section along the line IIII of Fig. 1:

Fig. 3 is an end view of the propeller hub;

Fig. 4 is a section along the liney IV-IV of Fig. l;

Fig. 5 is a diagram of the electric controls;

Fig. 6 is a sectional view of an adjustable device for automatically controlling the pitch variation; f

Fig. 7 is a similarsection to that of Fig. 1 and shows the application of the invention to two coaxial propellers having their shafts invariably connected to each other and driven for, example by the same engine, Y y,

. Fig. '7.a is a fragment of the right hand endof Fig. '7 illustrating a modification of the invention, and

Fig. 8 is a view similar to that of Fig. 7 and illustrates a modification of the arrangement shown in Fig. 7.

In the embodiment of Fig. 1, the propeller hub I which is fixed on the propeller shaft 2 has its length reduced substantially to the diameter of the cases 3 of the blade roots 4. Each blade root 4 carries at its base a spur gear 5 meshing with a rack 6 carried by an internally screw-threaded and nonrotatable sleeve 1 screw-threaded on a screw 8 having its axis parallel with the prupelier shaft 2 and supported by bearings 9 belonging to the case 3; said screw abuts endwise against its two bearings and is extended outside the case 3 by a bearing surface on which is Xed a gear I0 which meshes with a gear II loosely mounted on the propeller shaft 2; these members 5 to I0 as a whole form afv group the eiect of which, when it becomes operative, is to move the corresponding blade about its own axis; the hub I supports a number of similar groups which are distributed near the various blades and are equal in number to that of the blades; the gear II meshes with the gears ID of these various groups and consequently forms adriving member which` is common to these various groups. Said gear I I is secured to a spur gear I2 with which meshes a gear I3 fast on the end of a shaft I4 which is parallel with the shaft 2 and is journaled in bearings I5 of a support I6 having the shape of a case. Said support I6 in which is journaled the front end of the shaft 2 is fixed on the supporting case of said propeller shaft. VOn the shaft I4 inside the case I6 are loosely mounted the winding carrier-plates I8, I9 of two electro-magnetic clutches having the same armature 20 carrid between said two plates I8, I9 by a plate 2l fast on the shaft I4 and resiliently deformable transversely. The plate I8 carries a gear 22 meshing with a gear 24 fast on the shaft 2A and the plate I9 carries a gear 23 meshing with a gear 26 likewise fast on the shaft 2. Conducting rings 28 which are fixed on the plates I6, I9 and rub against brushes 29 carried by the case I6, serve for the feed and thel return of the supply current for the windings of said electro-magnetic clutches. VThe transmission ratioof the gear v24--22 is very slightly lower vthan that of the gear I 2-I 3 which is itself very slightlylower than that of the gear 6-,25. f

On said shaft I4 is furthermore 1fixed another `armature 3| which is similar to the armature 20 and cooperates with two winding-carrier plates 32 and 33, one of which, 32. is fixed to the case I6 and the other of which, 33. is loosely mounted on the shaft I44 and carries a gear 34 meshing with a gear 35 fast on the shaft. 2; the supply of the winding of the plate 33 is eii'ected by means of rings 28 and brushes 29 as for the clutches I8 and I9. The transmission ratio of the gear 33-34 is very much higher than that of the gear 24-22.

The operation is as follows:

When none of the clutches I8, I9, 32, 33 is engaged, it is obvious that the gears III carried by the hub of the propeller drive the gear II at the same speed as the propeller as though it were integral with the hub I; the gear I2 thus rotates the shaft I4 at a speed which depends on the transmission ratio of the gear I2-I3. On the other hand, the gears 24-22 and 26-25 respectively rotate the plates I8 and I9 at speeds, one of which is very slightly higher and the other very slightly lower than that of the shaft I4; the difference of speed between the two members 28 and I 8, on the one hand, and 20 and I9, on the other hand, of each clutch is therefore very reduced and may be chosen by construction as small as desired. If current is passed through the winding of the plate I8, the armature 20 is attracted and the shaft I4 is compelled to rotate at the speed of the plate I8 which is slightly higher than that at which it is 'previously rotated; it ensues that the gears I2 and II are compelled to rotate slightly faster than the shaft 2 and they consequently rotate each wheel I about its own axis, thereby causing, by rotating the screw 8, a longitudinal movement of the nuts 1 and a variation of the pitch of the blades. By passing the current through the winding of the plate I9, the gears II and I2 are similarly caused to rotate slightly slower than the shaft 2, thereby causing a variation of pitch in the opposite direction to the previous one.

When current is sent through one or other of the windings of the plates 32, 33, the variation of pitch is produced in a similar manner to that just described but at a much greater speed in order to produce a very quick reversal of the pitch, in a time of less than one second.

The supply of current to the electro-magnetic clutches can be effected, in the present exemplary embodiment, according to the diagram of Fig. 5. In said diagram, each plate I8, I9, 32, 33 carries two terminals 38 and 39 for the input and output of the current in its winding. The various terminals 38 are connected in parallel to one of the poles of a battery of accumulators 40, through the medium of the rings 28 and the brushes 29 as regards the rotating plates I8, I9 and 32. The terminals 39 of the plates I 8, I9 of the mechanism for the slow variation of the pitch are respectively connected to the two terminals 4I of a two way switch 42, the common terminal 43 of which is connected to a terminal 44a of another .two-way switch 45, the common terminal 46 of which is connected to the other pole of the battery 40. 'I'he other terminal 44h of the switch 45 is connected in parallel to the terminals 41 of two switches 48, the .two other terminals 49 of which are respectively connected to the terminals 39 of the plates 33 and 32. 'Ihe same pivoting handle 50 serves to actuate the switches 45 and 48; in the position shown, the contact exists between the terminals 46 and 44a and the switch 42 is thus connected to the battery 40; on the other hand, the contact is broken between the terminals 46 and 44h; by moving the handle 50 75 in one direction or the other, said handle breaks the contact between the terminals 48 and 44a and makes same between the terminals 46 and 44h, thereby connecting the two switches 48 to the battery, then the handle 50 actuates the switch 48 towards which it is pushed and the current is sent into one or the other of the plates 32, 33.

Furthermore, the supply circuits of the electro-magnetic clutches each include a switch 5I, 52, 53, 54, which is automatically controlled by the pitch indicator mechanism and breaks the circuit and stops the variation of the pitch or the reversal at predetermined values of the pitch. Said switches 5I to 54 are preferably grouped in the same chamber 55 (Figs. l and 4) through which passes the shaft 56 for actuating the pitch indicator and on which shaft are fixed four suitable cams 58. The mechanism for actuating the pitch indicator is of known type provided with a differential and will not be described herein.

The embodiment shown in the drawings furthermore includes a device for automatically actuating the switch 42 for the slow gradual variation of the pitch. For this purpose, said switch is provided with two contacts shaped like opposite segments of a circle and respectively connected to the terminals 4I on which is adapted to move a pivoting brush 6I, the spindle of which carries a gear 62 meshing with a toothed quadrant 63 carried by a pivoting lever 64, which is actuated by a centrifugal device 65, such as a centrifugal governor. It is also possible to use a chronometric tachometer for this purpose. Said instantaneous revolution-counter being driven by the engine moves the lever 64 in one direction or the other as soon as the speed of the engine deviates, more or less, from a predetermined value, the brush 6I moves on to one of the segments 60 and the corresponding clutch is supplied with current until the governor has returned the brush 6I to its neutral position between the two seg- -ments 68.

It will be noted that owing to the presence of the two-way switch 45, it ls impossible for the automatic variation mechanism and the reversing mechanism to operate simultaneously.

The arrangement of the centrifugal masses and of the spring is effected in such a manner that for a given dillerence of revolutions there is always substantially the same angular displacement of the lever 64, whatever be the speed of rotation. In this manner the range of adjustment is always the same.

The segments 60 of the switch 42 are carried by an angularly movable plate which is provided with a gear 6l engaging with a driving pinion 68 connected to a handle, not shown, within reach of the pilot and the displacement of which by the latter produces a rotation of said pinion 68 and consequently an angular displacement of the segments 60, thereby modifying the neutral position of the brush 6I and consequently the engine speed which has to be maintained by the governor.

On the part of the supply circuit which is common to the clutches I 8, I9 for the automatic slow variation of the pitch, between the stud 44a of the switch 45 and the pivoting brush 6I, is interposed a switch 69 which is actuatedl by the throttle control lever, for example through the intermediary of a cam, in such a manner as only to be closed beyond a predetermined degree of opening of said lever. Any automatic variation the event of a breakdown of the engine, it will sufiice to lock the shaft I4 by any means such as a brake, a dog, etc., in order to obtain the position of` least resistance assuming th /t the movement of the vehicle causes the pr peller to rotate; ifthe propeller cannot rotate because the engine is seized for any other reason, a driving `mechanism is added to the shaft I4. Said driving mechanism as shown in Fig. 7a, may include a clutch I4a and gears I4b fitted on the shaft I4 and adapted to be actuated by an emergency device such as an electric motor I4c orl by hand through a further gear I4d and a handwheel I4e.

The emergency mechanism is capable of rotating said shaft I4 in the reverse direction to that in which it normally rotates when the engine is rotating. i

The embodiment illustrated in Fig. 7 relates to the case of two propellers A, B, mounted one behind the other on two concentric shafts 12, 13, rotating in opposite directions to each other at the same speed or at any speeds but which are in a constant ratio with each other; this is the case for example of two propeller shafts driven by the same engine. In the embodiment shown, each propeller A, B, is provided, for varying the pitch of the blades, with a mechanism of the type of the one previously described and illustrated in Fig. 2. For actuating the mechanism of the propeller A fast on the inner shaft 12, behind said propeller A is arranged a gear IIa loosely mounted on the shaft 12 and secured to another gear I2a; said two gears IIa and I 2a perform the same function as the gears l I and I2 of the embodiment of Fig. 1. The gear I2a meshes with a planet gear 14 keyed on a shaft 15 parallel with the propeller shaft and rotatably journaled in the hub of the propeller B; on said shaft 15 is keyed behind the propeller B another planet gear 16 meshing with a spur gear 11 loosely carried'by the outer shaft 13 and secured to another gear I2b likewise loose on said shaft and driven by the gear I3 of an auxiliary shaft I4 identical with that of Fig. 1. An epicyclic transmission is thus formed having planet gears 14, 16, which are compelled to rotate in unison with each other and are loosely mounted on the propeller B fast on the outer shaft 13 and respectively meshing with sun gears I2a, 11 which are coaxial with the propellers and are arranged on either side of said propeller B, the gear I2a located between the two propellers being secured to said coaxial member IIa and the other, 11, being loosely mounted on the outer shaft 13 and drivenby the pitch varying mechanism I3, I4.

The gear I2b is further provided with a bevel gear 18 in mesh with a. counter-bevel pinion 19, located between the gears I2b and 11 and loosely journaled in a stationary support 80. Said bevel pinion 19 meshes with a bevel gear 8| secured to a gear IIb which is loose on the sleeve 82 connecting the gears I2b and 11 together and forming the coaxial member of the propeller B fast on the outer shaft.

As the gears IIa and IIb participate in the rotary movement of the propellers A and B and consequently rotate in opposite directions to each other, it is obvious that the gears IIb and I2b also rotate in opposite directions to each other at the same speed as the propellers; when the shaft I4 of the actuating mechanism rotates and thus accelerates or slows down the speed of the gear I2b, it is obvious that it'causes a simultaneous variation in the same direction of the pitch of the two propellers. In the case of propellers rotating at speeds which are different but are always in the same ratio, either positive or negative according to whether the propellers are'rotating in the same direction or in opposite directions, the pinion 1,9 is replaced by a transmission having a ratio which is equal to the ratio of the speeds, or again the epicyclic transmission is constructed in such a manner that its ratio is equal to the ratio of said speeds.

In the case of propellers rotating in the same directionat the same speed, the gear I Ib may be.

eliminated land the gear 11 in this case forms the coaxial member of the propeller B.

Referring now to the modified embodiment illustrated in Fig. 8, the essential difference between said embodiment and that of Fig. '1 is that the clutch members I8a, vI9a', which are loosely mounted on the auxiliary shaft I4a, are respectively driven by wheels 24a', 25a', which are keyed on a countershaftla' journaled in the case I6'. Said shaft Bla is driven in any desired manner fromA the engine actuating the propeller shafts, for instance, as shown, through the medium of an hydraulic clutch II2a carried by the shaft 8Ia and the driving element of which is provided with a gear I I4a. in mesh with a gear II6 fast on the propeller shaft 13.

The operation is quite similar to that described above with reference to Fig. '7 but it will be noted that the use of an intermediate shaft such as 8Ia may also be applied in the case of Fig. 1 and that it offers in particular the advantage of eliminating the large diameter gears 24, 25, 34 (Fig. 1) which it enables to be replaced by much smaller gears such as the gears 24a. 25a; such an arrangement furthermore and particularly offers this advantage of enabling the movement take-off to be effected at any point and the auxiliary shaft to be arranged in any manner relatively to the driving shafts of the propellers.

In all cases, the case I6 may form, with the auxiliary shaft, with or without a counter-shaft, an autonomous assembly which may be mounted as a unit on an existing engine or in any other appropriate spot in an aircraft.

Of course, the invention is in no way limited to the constructional details illustrated and de-` scribedwhich have only been given by way of example. Thus, in particular, without exceeding the scope of the invention, it is Vpossible to substitute mechanically, pneumatically or hy'- draulically actuated clutches of another type for the electromagnetic clutches; similarly,A the propeller need not have any reversing mechanism, the mechanism carried by the hub for driving each blade may be different from Vthe one described, the movement take-off for driving the shafts 8Ia', 8Ib may be effected at any point between the tatable relatively thereto, gear means adapted.

to operatively connect said coaxial gear to the propeller blades so that a rotation of said coaxial gear relative to the propeller will produce a variation of the pitch, motion transmitting means whereby said coaxial gear may be rotated relative to the propeller, said motion transmitting means including at least three gear trains adapted each to rotate said gear coaxial to the propeller and first. second, third and fourth clutches including driving and driven coupling parts, countershaft means supporting the driving and driven parts of said three first clutches and stationary bearing means for said countershaft means, the driven parts of said three clutches being in permanent driving connection with said coaxial gear and the three clutches arranged to selectively set said gear trains into and out of operative connection with said coaxial gear, the gear ratios of said three gear trains being, the

one slightly greater, the other slightly less and the third far higher than the gear ratio between said coaxial gear and the driven part of the associated clutch, means including said fourth clutch or coupling, one coupling part of which being in permanent connection with said coaxial gear, said last named means being adapted to alter rotation of said latter coupling part of the fourth clutch, and thereby of said coaxial gear, in a way contrary to that resulting from the operation of said third clutch and gear train, and control means for said four clutches.

2. A pitch varying and reversing device for aerial screw propellers, including means adapted to increase and decrease the pitch at any one of two widely different rates, wherein said means includes a rotatable countershaft, stationary bearing means supporting said countershaft, a gear fast on sai'i countershaft, a gear coaxial to the propeller and rotatable relatively thereto and in mesh with said gear carried by the countershaft, gear means adapted to operatively connect said gear coaxial to the propeller to the propeller blades so that a rotation of said coaxial gear relatively to the propeller will produce a variation of the pitch, first, second, third clutches carried by said countershaft, each of which having its driven part fast on the countershaft, pow er means, and at least three gear trains rotatably and respectively connecting the driving part of the irst, second and third clutches to the power means, the gear ratio of said three gear trains being, the one for the rst clutch slightly greater, the other for the second clutch slightly less and the third for the third clutch far higher than the gear ratio between said gear coaxial to the propeller and said countershaft, means including a fourth clutch or coupling including two cooperating coupling parts, one of which being secured on said countershaft, said last named means being adapted to alter rotation of said latter coupling part of the fourth clutch, and thereby of said coaxial gear, in a way contrary to that resulting from the operation of said third clutch and gear train, and control means for said four clutches.

3. A pitch varying and reversing device as in claim 1 wherein said four clutches are electromagnetic clutches and the control means therefor includes an electric source, a two way switch, two separate wire means from two separate terminals of said switch to the two iirst named electromagnetic clutches. wire means from said clutches to one and the same pole of said source, a control two-way switch, a wire from the common contact stud of said rst named two-way switch tc one of the contact studs of said control switch, the contact stud of the latter that is common to both ways being connected to the other pole of said source, wire means from the other separate stud of said control switch to said two other electromagnetic clutches, respectively, a switch in each of said wire means. wire means from said two last named clutches to the first named pole of the source, and manually operable control means for simultaneous control of said control switch and each of said last named switches.

4. In a pitch varying mechanism for propelling means including two aerial propellers with variable pitch, coaxially arranged one behind the other, each of which includes a hub and propeller blades rotatably carried by said hub, and two concentric inner and outer propeller shafts respectively carrying said propellers, a transmission member associated with the propeller carried by the inner shaft and arranged between said two propellers and coaxially thereto, a plurality of motion transmitting contrivances carried by the hub of the propeller fast on the inner shaft and respectively connecting said transmission member to the various blades of this propeller and adapted to transform a motion of the transmission member relatively to the propeller shaft into a pitch varying motion of the blades, an epicyclic transmission including sun gears and planet gears said planet gears being carried by the propeller fast on the outer shaft and compelled to rotate in unison with each other and said sun gears being arranged on either side of and coaxially to said propeller, carried by the outer shaft, the sun gear located between the two propellers being so connected to said transmission member that an angular motion of said sun gear relatively to the inner shaft will cause a motion of said transmission member relatively to the same shaft, driving means adapted to cause an angular motion of the other sun gear, and control means for said driving means,

5. In a pitch varying mechanism as in claim 4, common power means for rotating both said propeller shafts, a motion transmitting means arranged on the same side of the propeller on the outer shaft as the sun gear around said shaft, coaxially therewith, and movable relatively to said shaft, said motion transmitting means being connected to said driving means to be actuatable thereby and a plurality of motion transmitting contrivances carried by the propeller fast on the outer shaft and respectively connecting said motion transmitting means to the various blades to transform a motion of said means relatively to the outer shaft into a pitch varying motion of the blades.

6. In a pitch varying mechanism as in claim 4, separate power means for rotating separately said propeller shafts, a motion transmitting means arranged on the same side of the propeller on the outer shaft as the sun wheel around said shaft, coaxially therewith, and movable relatively to said shaft, said motion transmitting means being connected to the various blades to transform a motion of said means relatively to the outer shaft into a pitch varying motion of the blades and separate actuating mechanism for independently moving said transmission member and motion transmitting means relatively to the associated shaft.

7. A pitch varying and reversing device as in claim 1 wherein said gear wheel trains include at least one auxiliary countershaft and stationary bearing means rotatably supporting the latter.

8. A pitch varying device as in claim 1 wherein said stationary bearing means consists in a separate casing forming with the motion transmitting means carried thereby a self-contained and separately removable unit.

9. A pitch varying and reversing device for aerial screw propellers including means adapted to increase and decrease the pitch at any one of two widely different rates, wherein said means includes a gear coaxial to the propeller and rotatable relatively thereto, gear means adapted to operatively connect said coaxial gear to the propeller blades so that a rotation of said coaxial gear relative to the propeller will produce a variation of the pitch, motion transmitting means whereby said coaxial gear may be rotated relative to the propeller, said motion transmitting means including at least three gear trains adapted each to rotate said gear coaxial to the propeller and three stationary supported clutches including driving and driven parts, said driven parts being in permanent driving connection with said coaxial gear and the clutches being respectively associated to said gear trains to selectively set them into and out of operative connection with said coaxial gear, the gear ratios of said three gear trains being, the one slightly greater, the other slightly less and the third far higher than the gear ratio between said coaxial gear and the driven part of the associated clutch, means including a fourth clutch or coupling including two cooperating coupling parts, one of which being in permanent driving connection with said coaxial gear, said last named means being adapted to alter rotation of that connected part of said fourth clutch and thereby of the coaxial gear in a way contrary to that of said third gear train, and control means for said four clutches.

l0. A pitch varying and reversing device for aerial screw propellers as in claim 9, further including propeller driving means in permanent driving connection with the driving parts of said three clutches,

l1. A pitch varying and reversing device for aerial screw propellers as in claim 9, further including at least one auxiliary countershaft forming part of said gear wheel trains and in permanent driving connection with at least some of the driving parts of said three clutches, and a propeller driving shaft connected to said auxiliary countershaft to be able to rotate the latter.

12. A pitch varying and reversing device for aerial screw propellers as in claim 9, further including propeller driving means in permanent driving connection with the driving parts of said three clutches, and emergency motion transmitting means separately actuatable, i. e. otherwise than from said propeller driving means, and connected to said driving parts to be adapted to rotate the latter, so that the pitch can be varied even when said propeller driving means are not in operation.

13. A pitch varying and reversing device`as claimed in claim 2, further provided with emergency motion transmitting means separately actuatable otherwise than from said power means and connected to said countershaft, the latter being thus enabled to be rotated thereby so that the pitch can be varied even when said power means are not in operation.

14. A pitch Varying and reversing device as claimed in claim 2, further provided with emergency power means connected to said countershaft to rotate the latter and thereby vary the pitch when said propeller actuating power means is not in operation.

CHARLES RAYMOND WASEIGE. 

